1. Field of the Invention
This invention is directed to an apparatus and to a system. More specifically, this invention concerns an electro-mechanical locking mechanism and to a system for control of such mechanism.
2. Description of the Prior Art
Electro-mechanical locks have and continue to be used in a variety of environments, including the traditional bank-type vaults (security safes); door locks for home and automobile; and security locks for prison cells and other places of confinement.
Generally such locks include a bolt or latching mechanism which can be manually or electrically engaged, a blocking mechanism which prevents the bolt or latch from disengagement (opening); and an electric or electronic means for activation and inactivation of the blocking mechanism. In the context of this discussion, the phrase "blocking mechanism" is intended as descriptive of a mechanical impedance to movement of the bolt or latch which is associated therewith to prevent its inadvertent movement.
The following patents are illustrative of the relevant prior art: U.S. Pat. Nos. 4,686,912; 4,685,709; and 4,982,585.
U.S. Pat. No. 4,686,912 (to Fogleman, et al) describes an electrically controlled latching mechanism which enables a door to be released by either a mechanical combination lock or by an electrical lock control circuit. The Fogleman device is reportedly useful for adaptation to "in-room" hotel or motel safes. In Fogleman, the combined action of electronic locking mechanism and solenoid cause a pair of reciprocating locking bars, located within the vault door, to move or engage a catch within the vault door frame, thereby locking the vault (Column 3, Line 39-46). A key pad is provided to allow the user to input an alpha-numeric code (access code) to cause an electronic circuit to energize the bolt and thereby cause it to retract unlocking the vault door. In the Fogleman patent, the intricacies of solenoid activation are set forth in FIG. 2 thereof. The solenoid activation apparently moves a pivotally mounted lever, causing reciprocal movement of a locking bar mechanically affixed to opposite end of the lever. It would appear that a single solenoid is utilized to lock the vault.
U.S. Pat. No. 4,685,709 (to Kambic) describes a complex locking mechanism for a jail cell door. In brief, the primary locking mechanisms are motor driven, and upon appropriate activation can lock or unlock the jail cell door. Alternatively, a single solenoid can activate and inactivate the same locking mechanism. In the event there is a power failure, when the doors are locked a "fail-safe" feature is provided to return the door lock to the lock position (FIG. 11 and accompanying description at Col. 8, line 23-53). This is achieved by simply providing a biasing spring relative to the solenoid associated with a linkage to power the latch activating mechanism. Upon loss of power, the solenoid is de-energized and the opposing spring activates the latching mechanism, thus locking the cell door.
U.S. Pat. No. 4,982,585 (to Davis, et al) describes a timer for bank vaults for use in conjunction with a pair of solenoids and a mechanical latch for locking of the vault door. In brief, an energizing signal causes one of the two solenoids to release a floating, latching cam (reference numeral 144). The floating latching cam is caused to move in a downward direction by a spring biasing means (reference numeral 142). The relative movement of the floating cam causes the plate (reference numeral 74) to move in the same relative direction, thereby affecting latching (unlatching) of the vault door.
As is evident from the foregoing, electro-mechanical locking mechanisms have become increasingly complex, requiring redundant or back-up systems in the event of failure and are generally ill-adapted for simple and cost effective applications (i.e. hotel rooms and home security environments). Accordingly, there is a continuing need for a simple yet effective design for an electro-mechanical lock which is free from the shortcomings as set forth hereinabove.